Blunting specific T-dependent antibody responses with engineered “decoy” B cells

• Published in: Molecular therapy Vol. 32; no. 10; pp. 3453 - 3469
• Main Authors: Pitner, Ragan A., Chao, Jaime L., Dahl, Noelle P., Fan, Meng-Ni, Cai, Xiaohe, Avery, Nathan G., Roe, Kelsey, Spiegel, P. Clint, Miao, Carol H., Gerner, Michael Y., James, Richard G., Rawlings, David J.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 02.10.2024
• Subjects: Adoptive Transfer; Animals; antibody; Antibody Formation - immunology; antibody inhibitors; B cell engineering; B-Lymphocytes - immunology; B-Lymphocytes - metabolism; Blimp1; cell therapy; CRISPR; CRISPR-Cas Systems; Factor VIII - genetics; Factor VIII - immunology; gene therapy; Germinal Center - immunology; Germinal Center - metabolism; germinal centers; hemophilia; Humans; immune tolerance; Immunoglobulin G - immunology; Mice; Mice, Knockout; Positive Regulatory Domain I-Binding Factor 1 - genetics; Positive Regulatory Domain I-Binding Factor 1 - immunology; Positive Regulatory Domain I-Binding Factor 1 - metabolism; T-Lymphocytes - immunology; T-Lymphocytes - metabolism; hemophilia; CRISPR; immune tolerance; antibody; B cell engineering; cell therapy; germinal centers; gene therapy; Blimp1; antibody inhibitors
• ISSN: 1525-0016; 1525-0024; 1525-0024
• DOI: 10.1016/j.ymthe.2024.08.023

Antibody inhibitors pose an ongoing challenge to the treatment of subjects with inherited protein deficiency disorders, limiting the efficacy of both protein replacement therapy and corrective gene therapy. Beyond their central role as producers of serum antibody, B cells also exhibit many unique properties that could be exploited in cell therapy applications, notably including antigen-specific recognition and the linked capacity for antigen presentation. Here we employed CRISPR-Cas9 to demonstrate that ex vivo antigen-primed Blimp1-knockout “decoy” B cells, incapable of differentiation into plasma cells, participated in and downregulated host antigen-specific humoral responses after adoptive transfer. Following ex vivo antigen pulse, adoptively transferred high-affinity antigen-specific decoy B cells were diverted into germinal centers en masse, thereby reducing participation by endogenous antigen-specific B cells in T-dependent humoral responses and suppressing both cognate and linked antigen-specific immunoglobulin (Ig)G following immunization with conjugated antigen. This effect was dose-dependent and, importantly, did not impact concurrent unrelated antibody responses. We demonstrated the therapeutic potential of this approach by treating factor VIII (FVIII)-knockout mice with antigen-pulsed decoy B cells prior to immunization with an FVIII conjugate protein, thereby blunting the production of serum FVIII-specific IgG by an order of magnitude as well as reducing the proportion of animals exhibiting functional FVIII inhibition by 6-fold. [Display omitted] Rawlings and colleagues demonstrate that high-affinity non-differentiating B cells outcompete endogenous B cells in germinal centers following exposure to foreign antigen. These “decoy” B cells selectively blunt the generation of antibodies to cognate and cis-linked antigen, and they exploit this effect to block the generation of factor VIII-specific clotting inhibitors.